Insights into the epidemiology of Pierce's disease in vineyards of Mallorca,Spain

Xylella fastidiosa (Xf), the causal agent of Pierce's disease (PD), has long been considered a major threat to prosperous European viticulture. In May of 2017, PD was officially detected on a grapevine in Mallorca. To better understand the epidemiology of the first established outbreak of PD in Europe, the disease incidence and severity were assessed, vector transmission experiments were performed, and cultivar responses to Xf infections both in the field and in inoculation experiments were monitored. The genetic structure of Xf local populations was also investigated by multilocus sequence typing analysis, and their whole genome sequences and phylogenetic positions compared with respect to PD strains worldwide. Disease incidence was moderately low (0.07) and highly variable, ranging from 0.0 to 0.99. Its economic impact on wine production was considered low. Vineyards managed under conventional viticulture were significantly less infected than organic farming. Under greenhouse conditions, the insect Philaenus spumarius efficiently transmitted the pathogen from infected to healthy grapevines. In the inoculation experiments, Xf infected, to some degree, 29 of the 30 cultivar × rootstock combinations (n = 239). Cultivars Viura, Gorgollasa and Sauvignon Blanc were the most susceptible ones. All Xf isolates from grapevines belonged to sequence type ST1; they phylogenetically clustered within the Californian ST1 clade, with which they shared a 99.94% identity and the same plasmid. In addition, ST1 caused almond leaf scorch disease, where notably its incidence (0.78) and severity was much higher than PD. The likely reasons for these wide differences are discussed in the context of a 20-year Xf introduction scenario.     

Responses in the absorptive phase in muscle and liver protein synthesis rates of growing rats.

The effect of time after beginning of a meal (30, 60, 90 and 120 min) on liver and gastrocnemius muscle protein synthesis was tested in growing male rats using the large dose technique, based on a 10 min exposure to [15N]phenylalanine. The fractional synthesis rate was estimated from the ratio between the atom percent excess of tissue protein-bound and free labelled phenylalanine. The latter was measured by gas chromatography mass spectrometry using the tertiary-butyldimethylsilyl amino acid derivatives. The protein-bound phenylalanine of gastrocnemius muscle was separated from the other amino acids using preparative amino acid chromatography and then oxidised to N2 in an automated carbon-nitrogen Roboprep (CN) combustion module attached to a continuous flow isotope ratio mass spectrometer (IRMS), with m/z ions 28 and 29 monitored. The protein-bound phenylalanine from liver was separated by a gas chromatograph attached to a sample preparation module and an isotope ratio mass spectrometer (GC C-IRMS), with again m/z ions of 28 and 29 monitored. The following results were obtained: the daily fractional protein synthesis rates (ks) in gastrocnemius muscle and liver were 13.9% and 65.6% respectively, in 12 h fasted 145 g rats. These ks increased within 30 min after ingestion of meal to 14.9% and 91.8% for muscle and liver, respectively, and remained at these values for the next 90 min (14.6% and 87.4% at 60 min, and 14.3% and 88.6% at 120 min after the beginning of feeding). It was concluded that measurement of protein synthesis rates characteristics for the absorptive phase can be undertaken in a period from thirty minutes to two hours after start of a meal, without significant changes in the ks values.     

Structural characterization of the lignin in the cortex and pith of elephant grass (Pennisetum purpureum) stems

The structure of the lignin in the cortex and pith of elephant grass (Pennisetum purpureum) stems was studied both in situ and in isolated milled "wood" lignins by several analytical methods. The presence of p-coumarate and ferulate in the cortex and pith, as well as in their isolated lignins, was revealed by pyrolysis in the presence of tetramethylammonium hydroxide, and by 2D NMR, and indicated that ferulate acylates the carbohydrates while p-coumarate acylates the lignin polymer. 2D NMR showed a predominance of alkyl aryl ether (β-O-4') linkages (82% of total interunit linkages), with low amounts of "condensed" substructures, such as resinols (β-β'), phenylcoumarans (β-5'), and spirodienones (β-1'). Moreover, the NMR also indicated that these lignins are extensively acylated at the γ-carbon of the side chain. DFRC analyses confirmed that p-coumarate groups acylate the γ-OHs of these lignins, and predominantly on syringyl units.     

Comparison of major and trace element concentrations in 16 varieties of Cuban mango stem bark (Mangifera indica L.)

An aqueous decoction of mango (Mangifera indica L.) stem bark (MSB) has been developed in Cuba on an industrial scale to be used as a nutritional supplement, cosmetic, and phytomedicine, with antioxidant, anti-inflammatory, analgesic, and immunomodulatory properties. The concentration of major and trace elements was determined for 16 varieties of MSB belonging to two cultivars and grown in Cuba in the same soil (red ferralytic). Plants were classified into two groups, according to the tree age (12 and 26 year olds) and were analyzed for As, Ca, Cd, Cu, Fe, Hg, K, Mg, Pb, Se, and Zn content by means of ICP-AES technique. Experimental data were processed by ANOVA and principal component analysis in terms of elements, variety, and plant age, to choose the most adequate varieties for industrial purposes.     

Restricting inbreeding while maintaining selection response for weight gain in Mus musculus

An experiment with mice was designed to test the relative efficiency of three selection methods that help to minimize the rate of inbreeding during selection. A common house mice (Mus musculus) population was selected for 17 generations to increase the weight gain between 21 and 42 days. The population was split at random into three lines A, B and C where three selection methods were applied: individual selection and random mating, weighted selection with random mating and individual selection with minimum coancestry mating, respectively. There were three replicates for each line. Cumulated selection response was similar in the three lines, but there were differences in the level of inbreeding attained (in percentage): 31.24 (method A), 24.72 (method B) and 27.88 (method C). As consequence, lines B and C (weighted selection and minimum coancestry) showed a lower value of deterioration of fitness traits (the intrauterine mortality and the mortality at birth) than line A (random mating).     

Photofragment helicity caused by matter-wave interference from multiple dissociative states

Isolated diatomic molecules of iodine monochloride (ICl) were photodissociated by a beam of linearly polarized light, and the resulting ground-state Cl atom photofragments were detected by a method that is sensitive to the handedness (helicity) of the electronic angular momentum. It was found that this helicity oscillates between "topspin" and "backspin" as a function of the wavelength of the dissociating light. The helicity originates solely from the (de Broglie) matter-wave interference of multiple dissociating pathways of the electronic excited states of ICl. These measurements can be related to the identity and to the detailed shapes of the dissociating pathways, thus demonstrating that it is possible to probe repulsive states by spectroscopic means.     

Toxoplasma gondii infection in Colombia with a review of hosts and their ecogeographic distribution

Toxoplasma gondii is one of the most prevalent zoonotic protozoan parasites among warm‐blooded animal populations (humans included) around the world, causing multiple clinic manifestations including death in the most severe cases of infection. Due to the versatile life cycle of T. gondii and its diversity of potential hosts, there is a common perception that natural areas and wildlife are highly prevalent reservoirs for the parasite; however, information and reports of the parasite on wildlife populations in Colombia are scarce. Using PRC‐based detection analyses of the B1 gene, we evaluated the presence of T. gondii in 49 native small mammal species (10% of the mammal species of Colombia) from 4 different undisturbed natural habitats. Additionally, to understand the ecogeographical distribution of the parasite in Colombia, we developed a literature search of infection reports including information on the host species, density of records and occurrence patterns (using landcover and ecoregions) in natural, rural and urban areas. Our literature review showed a total of 8,103 reports of T. gondii for Colombia of which 86% were related to humans, and 14% to non‐human mammals and other categories, with just a single report associated to wildlife; additionally, 82% of all reports were associated to urban areas whereas only 18% to rural sites. Based on the negative results for the presence of T. gondii in our PCR‐based analyses and our literature search, we suggest that T. gondii has a synanthropic distribution in Colombia occurring in ecoregions as variable as the xeric scrubs in the northern lowlands and humid montane Andean forests, also we show a lack of information on the parasite relationship with wildlife, a concerning fact given that zoonoses are the leading mechanism for the emergence of infectious diseases.     

Isolation and identification of Babesia ovis in Extremadura (Spain).

A morphological and morphometric comparison was made of a Babesia ovis strain isolated in Extremadura (Spain) and a B. ovis strain from Turkey. Strains were morphologically similar, with a clear predominance of single sub-spherical or anaplasmoid forms. The use of an image analyser to measure B. ovis merozoites revealed significant differences in the long axis, short axis and volume between the two strains. Both strains however behaved in a similar manner in the indirect fluorescent antibody (IFA) test, which suggests a high degree of common antigenicity, despite morphometric differences. Conversely, no cross-reaction was observed between these strains of B. ovis and the other antigens used: B. motasi (The Netherlands), B. motasi (Turkey), B. crassa (Iran) and Theileria ovis (Turkey). B. ovis is therefore considered to be the aetiological agent of babesiosis in the area under study.